1. Field of the Invention
The present invention relates to image data correction method and lithography simulation method.
2. Description of the Related Art
With high integration and scale-down of semiconductor devices, it is important to predict lithography latitude from a mask pattern actually formed on a photo mask with high precision.
JPN. PAT. APPLN. KOKAI Publication No. 2004-37579 has proposed the following method as a method of predicting the lithography latitude from a two-dimensional pattern of an actual mask. According to the method, a mask pattern image is acquired using an SEM, and carry out lithography simulation using the outline data extracted from SEM image.
The mask pattern image is acquired using an image acquiring apparatus such as scanning electron microscope (SEM). However, image distortion exists in the image acquiring apparatus in general; for this reason, it is difficult to acquire micro pattern image. For example, image distortion resulting from the distortion of scan beam exists in the foregoing SEM. For this reason, there is a problem that an error of the edge position of outline data extracted from images having distortion gives a large influence to the lithography simulation result.
Japanese Patent No. 2687781 has proposed the following method as a method of correcting the image distortion. According to the method, correction data is previously obtained from image data of a reference pattern, and then, image data of a target pattern is corrected using the correction data.
However, according the foregoing conventional method, data becomes huge to correct the image data of the entire target pattern. This is a factor of causing a problem that it takes much time to make calculation for correction. Consequently, it is difficult to perform highly precise correction for the image pattern in small amount of data at high speed.